1. Field of the Invention
The present invention relates to a rotary structure for relaying signals, for example, a rotary structure for relaying signals which can be rotated such that a display module of a portable cellular phone can be twisted.
2. Description of the Related Art
Conventionally, as a portable cellular phone, there has been known a portable cellular phone which supports a display module on a manipulation module using a hinge by way of a support body such that the display module can be opened and closed. Particularly, when the portable cellular phone requires a large number of signal lines, to miniaturize the device and to prevent the fatigue disconnection of the signal lines attributed to the repeated operations of the display module, the manipulation module and the display module are electrically connected by way of a flexible printed wiring film for relaying signals.
However, with respect to the above-mentioned portable cellular phone, it is impossible to rotate the opened display module in a twisting manner so that the manipulation method is limited whereby the portable cellular phone exhibits poor availability. To cope with this situation, it may be possible to use a large number of harnesses in bundle to manipulate the above-mentioned display module in a twisted form. However, when it is necessary to transmit a large volume of information, the number of harnesses is increased and hence, the twisting manipulation becomes difficult, the miniaturization of the device becomes difficult, and the disconnection is liable to occur. Accordingly, the use of the flexible printed wiring film has been considered. However, when the twisting action is applied to the film, a complicated inner stress is generated in the inside of the printed wiring film thus arising a problem that the printed wiring is liable to be peeled off and disconnected.
The present invention has been made in view of the above-mentioned drawbacks and it is an object of the present invention to provide a rotary structure for relaying signals which can relay signals without disconnecting a large number of signal lines and can save a space.
To achieve the above-mentioned object, a rotary structure for relaying signals according to the present invention comprises a fixed frame which is supported and fixed in the inside of a casing, a rotary shaft which is rotatably inserted into a through hole of the fixed frame and has a distal end thereof projected to the outside of the casing, a rotary frame which is disposed outside the casing and is fixed to the distal end of the rotary shaft such that the rotary frame is integrally rotatable with the rotary shaft, and a flexible printed wiring film which has a distal end thereof pulled out to the outside of the casing along the rotary shaft and wound around a winding tongue of the rotary shaft which is positioned in the inside of the casing.
Due to such a constitution, according to the present invention, when the rotary frame is rotated, the rotary shaft is rotated so as to neatly wind the printed wiring film. Accordingly, even when the rotary frame is repeatedly rotated, a complicated inner stress is not generated in the inside of the printed wiring film and hence, there is no possibility that the printed wiring is peeled off or is disconnected.
Further, by printing a large number of signal lines to the printed wiring film, it is possible to obtain the miniaturized device which can transmit a large volume of signals.
According to an embodiment of the present invention, a holding member which includes a winding tongue and constitutes a part separate from the rotary shaft may be assembled to one end of the inside of the casing of the rotary shaft.
According this embodiment, since the printed wiring film can be wound around the holding member which constitutes a part separate from the rotary shaft, the degree of freedom in designing can be expanded.
According to another embodiment of the present invention, on at least one side of the fixed frame, a position restricting portion which is engaged with a winding portion of the printed wiring film is mounted so as to prevent the printed wiring film from being entangled.
According to this embodiment, the printed wiring film can be smoothly wound or released thus further enhancing the durability of the printed wiring film.
As another embodiment of the present invention, rotation restricting means which restricts a rotational movement of the rotary frame is mounted on the fixed frame.
According to this embodiment, the rupture of the printed wiring film attributed to the excessive rotation of the rotary frame can be prevented.
As another embodiment of the present invention, a resilient ring which ensures a so-called click feeling is arranged between the fixed frame and the rotary frame.
According to this embodiment, a manipulation feeling is enhanced so that the availability is enhanced.
As another embodiment of the printed wiring film according to the present invention, on at least one end of a straight winding portion of the printed wiring film, an extension portion which extends in the direction orthogonal to an axis of the winding portion may be formed.
To be more specific, on one end of a straight winding portion of the printed wiring film, a first extension portion which extends in the direction orthogonal to an axis of the winding portion is formed, and on the other end of the winding portion, a second extension portion which is arranged orthogonal to an axis of the winding portion and extends in the direction opposite to the first extension portion may be formed.
According to this embodiment, since the winding portion and the extension portions are separated by arranging them to become orthogonal to each other, a complicated inner stress is not generated in the printed wiring film so that the printed wiring is hardly peeled off or disconnected.
Particularly, the second extension portion of the printed wiring film may have a bent planar shape.
According to this embodiment, when the second extension portion is wound, portions thereof are not overlapped to each other and hence, it is possible to obtain an advantageous effect that the second extension portion can be easily pulled out.